routing. how do we route a physical package to someone, what route does the mail carrier take?. is where the networking term stems from.

you don't really need to know exactly who or where the target house (or IP) is, you just sorta need to know what post office or trucks serve that area (or which networks connect to your target IP / next hop).

thats up to your local post office (or switch) -- send it to them and let them figure it out, which routes and truck to take to get there, like which routes will eventually pass through this locality?

sometimes that's simple and geographical, like a big city and the local post office serves the people around you, 10 miles in any direction, and sometimes it's because there is a mail truck that drives up and down a valley serving people on multiple sides of a state line and in multiple towns.

back in the day, before cars, those routes could be multi-day treks.

also consider that USPS is federal and plays by federal jurisdiction rules, meaning that they don't really care about neat and tidy state or municipal lines -- they're valid everywhere.